<template>
  <div>
    <router-link tag="div" to="/" class="header-abs" v-show="showAbs">
      <div class="iconfont iconfanhui back-abs-icon"></div>
    </router-link>
    <div class="header-fixed" v-show="!showAbs" :style="opacityStyle">
      <router-link to="/">
        <div class="iconfont iconfanhui header-fixed-back"></div>
      </router-link>
        景点详情
    </div>
    
  </div>
</template>
<script>
export default {
  name: 'DetailHeader',
  data(){
    return {
      showAbs: false,
      opacityStyle: {
        opacity : 0
      }
    }
  },
  methods: {
    handleScroll(){
      console.log('scroll')
      let top = document.documentElement.scrollTop 
      || document.body.scrollTop
      || window.pageYOffset
      if( top > 60 ){
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = { opacity }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  },
  mounted (){
    window.addEventListener('scroll', this.handleScroll)
  },
  destroyed (){
    window.removeEventListener('scroll')
  }
}
</script>
<style lang="stylus" scoped>
  @import '~styles/varibles.styl'
  .header-abs
    position absolute
    left .2rem
    top .2rem
    width .8rem
    height .8rem
    border-radius .4rem
    background rgba(0,0,0,.8)
    text-align center
    line-height .8rem
    .back-abs-icon
      color #fff
  .header-fixed
    position :fixed
    top 0
    left 0
    right 0
    text-align :center
    line-height :$headerHeight
    height :$headerHeight
    color :#fff
    background :$bgColor
    font-size :.32rem
    .header-fixed-back 
      position :absolute
      top :0px
      left :0px
      width :.64rem
      font-size :.4rem
      text-align :center
      color :#fff
</style>
